Ladders are a ubiquitous tool used in a wide variety of industrial and domestic environments. Ladders are an important tool, for example, in the construction trades. Ladders are also commonly found in homes, schools, and offices to facilitate repairs or the performance of routine maintenance, such as the trimming of trees, and the changing of light bulbs or signage. Ladders also serve highly useful purposes for firefighting and the maintenance of public utilities. Indeed, it is difficult to imagine life without ladders.
Some ladders, typically referred to as step ladders, are capable of standing alone to support a user. Another type of ladder, however, does not stand alone, but rather, must be leaned against a wall or other structure in order to support a user. Ladders of this type include extension ladders. Alternately, some step ladders may be used in a stand alone mode, or may be folded and leaned against a wall during use.
One disadvantage of ladders that must be leaned against a wall to support a user is that when the lower end of the ladder is positioned in a desired location by the user, the upper end of the ladder may coincide with a relatively fragile structure, such as a window or a rain gutter, that cannot support the weight of the user when the user climbs the ladder. Another disadvantage is that the upper end of the ladder may contact a portion of the wall that the user desires to paint or access. In such situations, the user must typically relocate the lower end of the ladder to a less desirable position to avoid the disadvantages associated with the position of the upper end, with the result that the user may be required to reach or lean away from the ladder to perform the desired task at the upper end of the ladder.
It is known to use various ladder attachment structures in an attempt to overcome some of the above-noted disadvantages. For example, U.S. Pat. No. 5,117,941 issued to Gruber teaches that a pair of brackets may be attached to the tips of the rails of the ladder, and a spacer member of sufficient length to span a window opening may be attached to the brackets in a cross-wise fashion to avoid having the tips of the rails of the ladder contact the window. Alternately, Gruber teaches that a platform may be attached to the brackets to provide a standoff from the wall. Similarly, U.S. Pat. No. 4,184,569 issued to Grenier teaches a pair of tubes or bars that are attached to the rails of the ladder that project outwardly toward the wall, providing a standoff between the upper end of the ladder and the wall. U.S. Pat. No. 4,159,045 issued to Brooks teaches a platform that is bolted to the rails that projects outwardly to provide the desired standoff. A similar apparatus is taught by Busenhart (U.S. Pat. No. 5,850,894) for operation of a ladder near interior or exterior corners of a building.
Although useful results have been achieved using the prior art attachment apparatus, some disadvantages exist. For example, prior art apparatus are characterized by being rigidly attached and not easily disassembled from the ladder. It is therefore no easy matter to remove such attachment apparatus from a ladder when it is no longer desired, or to facilitate storage and transportation of the ladder. Also, the prior art attachment apparatus are generally characterized as being relatively non-adjustable and having only a single operating position. Although some prior art attachment apparatus may be moved to different locations on the ladder, there is little or no ability to easily and efficiently change the configuration of the attachment apparatus to accommodate varying situations in which a standoff from the wall may be needed.